Activity determination of 59Fe by 4π beta–gamma counting using liquid scintillation in the beta channel. (March 2016)

• Record Type: Journal Article
• Authors: van Rooy, M.W.; van Staden, M.J.; Lubbe, J.; Simpson, B.R.S.
• Is Part Of: Applied radiation and isotopes. Volume 109(2016:Mar.)
• Page Start: 276
• Page End: 280
• Publication Date: 2016-03
• Subjects: Liquid scintillation coincidence counting -- Extrapolation technique -- Non-extrapolation method -- Iron-59; Radiology -- Periodicals; Radiation -- Industrial applications -- Periodicals; Nuclear chemistry -- Periodicals; Internet resource; Periodical; 660.298
• DOI: 10.1016/j.apradiso.2015.11.054
• Languages: English
• ISSNs: 0969-8043

Abstract

Abstract: This paper reports on absolute activity measurements of iron-59 made at the National Metrology Institute of South Africa (NMISA) via 4π(LS)β–γ coincidence counting. The exercise formed part of an Asia Pacific Metrology Program (APMP) regional key comparison. Source data were analysed by the extrapolation technique for a number of gamma-ray window settings. In addition, a feasibility study was undertaken on a second technique; a non-extrapolation method based on a detection efficiency analysis. The reported activity concentration of the 59 Fe solution was determined with a relative uncertainty of 0.28% ( k =1), the uncertainty being due mainly to the rate vs. efficiency fitting process. The result from the non-extrapolation method was lower than that given by extrapolation by 0.33%, within two standard deviations. Possible reasons for the small discrepancy are discussed. Highlights: We report on absolute activity measurements of 59 Fe made at the NMISA. Measurements were made via 4π(LS)β–γ coincidence counting. We compare results from extrapolation and non-extrapolation techniques. The techniques are based on efficiency analyses. The non-extrapolation result is lower than the extrapolation result by 0.33%.